BQMUSIC

I have been playing for over 20 years and I have had this hand/forearm cramping happen more and more over the last few years.. I have pin pointed it to times when I have either had an active week (gym, sports etc..) and not drinking enough water... especially combined with drinking booze..
Now I won't pretend that I don't like having a few pints when I play.. However.. if you hydrate properly.. you will not have this issue.. this is 99% an issue with you simply being dehydrated and your muscles letting you know... you left hand is working overtime and then it cramps.. try drinking beer all day and playing some sporting event - (beach vball, ball hockey etc...) and not hydrating properly...your legs will do the same things...) (it will be fun though!)
Drink LOTS of water every day... or at very least.. 2 - 3 days before show.. and cut back on your beers during the show) I usually ramp up on gatoraid a day or two before.. ad even bring a few to the show to sip on instead of a beer. NO MORE ISSUES...
have fun.. and happy cramp free playing!
BQ